Buggy code:
public void codeComplete ( char [ ] snippet , int insertion , int position , char [ ] [ ] localVariableTypeNames , char [ ] [ ] localVariableNames , int [ ] localVariableModifiers , boolean isStatic , CompletionRequestor requestor , WorkingCopyOwner owner ) throws JavaModelException { } public IField createField ( String contents , IJavaElement sibling , boolean force , IProgressMonitor monitor ) throws JavaModelException { } public IInitializer createInitializer ( String contents , IJavaElement sibling , IProgressMonitor monitor ) throws JavaModelException { } public IMethod createMethod ( String contents , IJavaElement sibling , boolean force , IProgressMonitor monitor ) throws JavaModelException { } public IType createType ( String contents , IJavaElement sibling , boolean force , IProgressMonitor monitor ) throws JavaModelException { } public boolean equals ( Object o ) { } public IMethod [ ] findMethods ( IMethod method ) { } public IJavaElement [ ] getChildren ( ) throws JavaModelException { } public IJavaElement [ ] getChildrenForCategory ( String category ) throws JavaModelException { } protected ClassFileInfo getClassFileInfo ( ) throws JavaModelException { } public IType getDeclaringType ( ) { } public int getElementType ( ) { } public IField getField ( String fieldName ) { } public IField [ ] getFields ( ) throws JavaModelException { } public int getFlags ( ) throws JavaModelException { } public String getFullyQualifiedName ( ) { } public String getFullyQualifiedName ( char enclosingTypeSeparator ) { } public String getFullyQualifiedParameterizedName ( ) throws JavaModelException { } public IJavaElement getHandleFromMemento ( String token , MementoTokenizer memento , WorkingCopyOwner workingCopyOwner ) { } public IInitializer getInitializer ( int count ) { } public IInitializer [ ] getInitializers ( ) { } public String getKey ( boolean forceOpen ) throws JavaModelException { } public IMethod getMethod ( String selector , String [ ] parameterTypeSignatures ) { } public IMethod [ ] getMethods ( ) throws JavaModelException { } public IPackageFragment getPackageFragment ( ) { } public String getSuperclassTypeSignature ( ) throws JavaModelException { } public String getSourceFileName ( ) { } public String getSuperclassName ( ) throws JavaModelException { } public String [ ] getSuperInterfaceNames ( ) throws JavaModelException { } public String [ ] getSuperInterfaceTypeSignatures ( ) throws JavaModelException { } public ITypeParameter [ ] getTypeParameters ( ) throws JavaModelException { } public String [ ] getTypeParameterSignatures ( ) throws JavaModelException { } public IType getType ( String typeName ) { } public ITypeParameter getTypeParameter ( String typeParameterName ) { } public String getTypeQualifiedName ( ) { } public String getTypeQualifiedName ( char enclosingTypeSeparator ) { } public IType [ ] getTypes ( ) throws JavaModelException { } public boolean isAnonymous ( ) throws JavaModelException { } public boolean isClass ( ) throws JavaModelException { } public boolean isEnum ( ) throws JavaModelException { } public boolean isInterface ( ) throws JavaModelException { } public boolean isAnnotation ( ) throws JavaModelException { } public boolean isLocal ( ) throws JavaModelException { } public boolean isMember ( ) throws JavaModelException { } public boolean isResolved ( ) { } public ITypeHierarchy loadTypeHierachy ( InputStream input , IProgressMonitor monitor ) throws JavaModelException { } public ITypeHierarchy loadTypeHierachy ( InputStream input , WorkingCopyOwner owner , IProgressMonitor monitor ) throws JavaModelException { } public ITypeHierarchy newSupertypeHierarchy ( IProgressMonitor monitor ) throws JavaModelException { } public ITypeHierarchy newSupertypeHierarchy ( ICompilationUnit [ ] workingCopies , IProgressMonitor monitor ) throws JavaModelException { } public ITypeHierarchy newSupertypeHierarchy ( IWorkingCopy [ ] workingCopies , IProgressMonitor monitor ) throws JavaModelException { } public ITypeHierarchy newSupertypeHierarchy ( WorkingCopyOwner owner , IProgressMonitor monitor ) throws JavaModelException { } public ITypeHierarchy newTypeHierarchy ( IJavaProject project , IProgressMonitor monitor ) throws JavaModelException { } public ITypeHierarchy newTypeHierarchy ( IJavaProject project , WorkingCopyOwner owner , IProgressMonitor monitor ) throws JavaModelException { } public ITypeHierarchy newTypeHierarchy ( IProgressMonitor monitor ) throws JavaModelException { } public ITypeHierarchy newTypeHierarchy ( ICompilationUnit [ ] workingCopies , IProgressMonitor monitor ) throws JavaModelException { } public ITypeHierarchy newTypeHierarchy ( IWorkingCopy [ ] workingCopies , IProgressMonitor monitor ) throws JavaModelException { } public ITypeHierarchy newTypeHierarchy ( WorkingCopyOwner owner , IProgressMonitor monitor ) throws JavaModelException { } public JavaElement resolved ( Binding binding ) { } public String [ ] [ ] resolveType ( String typeName ) { } public String [ ] [ ] resolveType ( String typeName , WorkingCopyOwner owner ) { } public String sourceFileName ( IBinaryType info ) { } protected void toStringInfo ( int tab , StringBuffer buffer , Object info , boolean showResolvedInfo ) { } protected void toStringName ( StringBuffer buffer ) { } public String getAttachedJavadoc ( IProgressMonitor monitor , String defaultEncoding ) throws JavaModelException { final String contents = getJavadocContents ( monitor , defaultEncoding ) ; if ( contents == null ) <START_BUG> throw new JavaModelException ( new JavaModelStatus ( IJavaModelStatusConstants . CANNOT_RETRIEVE_ATTACHED_JAVADOC , this ) ) ; <END_BUG> final int indexOfStartOfClassData = contents . indexOf ( JavadocConstants . START_OF_CLASS_DATA ) ; if ( indexOfStartOfClassData == ( - 1 ) ) throw new JavaModelException ( new JavaModelStatus ( IJavaModelStatusConstants . UNKNOWN_JAVADOC_FORMAT , this ) ) ; int indexOfNextSummary = contents . indexOf ( JavadocConstants . NESTED_CLASS_SUMMARY ) ; if ( indexOfNextSummary == ( - 1 ) ) { indexOfNextSummary = contents . indexOf ( JavadocConstants . CONSTRUCTOR_SUMMARY ) ; } if ( indexOfNextSummary == ( - 1 ) ) { indexOfNextSummary = contents . indexOf ( JavadocConstants . METHOD_SUMMARY ) ; } if ( indexOfNextSummary == ( - 1 ) ) { indexOfNextSummary = contents . indexOf ( JavadocConstants . END_OF_CLASS_DATA ) ; } if ( indexOfNextSummary == ( - 1 ) ) { throw new JavaModelException ( new JavaModelStatus ( IJavaModelStatusConstants . UNKNOWN_JAVADOC_FORMAT , this ) ) ; } return contents . substring ( ( indexOfStartOfClassData + ( JavadocConstants . START_OF_CLASS_DATA_LENGTH ) ) , indexOfNextSummary ) ; } public String getJavadocContents ( IProgressMonitor monitor , String defaultEncoding ) throws JavaModelException { } }

Fix:
return null ;